petroleum

1. Group 01
Mineral Resources and Technology
1

2. What is petroleum?
 Naturally occurring hydro carbon.
2 PETROLEUM
Major
C , H
Minor
O , S , N
Hydrocarbon Average
Paraffin's 30%
Naphthenes 49%
Aromatics 15%
Asphaltic 6%
Table 01: Composition of hydrocarbons by weights

3. Hydrocarbon Generation3
Two major phases of oil
generation:
 Oil window
• 100-150 °C 2.5-4.5 km
 Gas window
• 150-230°C

4. Countries where petroleum is produced4
• OPEC Countries – 42%
• Russia – 13%
• United States – 12%
• China – 5%
• Other oil producing
countries – 17%

5. Uses of Petroleum5

6. Formation of Petroleum
 Petroleum Systems
 Key Words
 Porosity
 Permeability
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Elements Processes
Source Rock Generation
Migration Route Migration
Reservoir Rock Accumulation
Seal Rock (Trap/ Cap Rock) Preservation

7. How Petroleum was formed?????7
Small
Organisms-
Planktons
Algae, Bacteria
T,P,W Extraction

8. How petroleum was created cont’d…,
 Pre-historic planktons (zoo planktons, Phytoplankton) were preserved in
the ocean basins.
 Eg:- Diatoms, Foraminifera, Radiolarian, Benthic algae
 OM mixed with mud were buried and covered with sediments.
 Temperature, Pressure, increased with depth.
 Chemical changes were occurred.
 Mainly under 3 steps
 Diagenesis- Sediments sedimentary rocks
 Catagenesis - Oil & gas formed
 Metagenesis
8
Phy, Chem, Bio

9. Kerogen
 Insoluble waxy substance derived from organic matter
 Algae, Wood, Pollen, Vitrinite etc..
 Found in various oil shale.
 Four kerogen types
 Contain different amount of H relative to O and C
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Kerogen Type Hydrocarbon Potential Amount of H
i Crude oil prone Higher
ii Crude oil & Natural gas prone Moderate
iii Gas prone Low
iv Inert material . Non-Prone None

10. Source Rock
 What is source rock?
 Sedimentary rock
 Contains sufficient organic matter (Hydrocarbons)
 Fine Grained
 When buried and heated, produce petroleum
 Preferable Conditions
 High productivity
 Stagnant Water Body
 Anoxic Conditions
 Swamps, Shallow seas, Coastal Upwelling, Lakes
 Quality depend on;
 Abundance of Organic Matter (OM)
 Preservation Potential
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11. Source Rock contd…
 Abundance of OM is determined by;
 Amount of Light, Water depth, Latitudes, Water temperature, Water turbidity, Abundance
of nutrients preferred by plants
 Preservation Potential (Conditions that favour the preservation of OM)
o Two important conditions
• Anaerobic conditions, Rapid sedimentation
• Maturity of Source rock is important to form oil / Gas
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12. Maturity of Source Rock
 Maturity?????
 Ability of the source rock to produce oil and (or) gas
 Depends on;
 Temperature and Pressure
 Age of source rock (At least 20 Ma)
 Maturity is measured by;
 Vitrinite Reflectance (R0)> 0.55
 TOC ( Total Organic Carbon) > 1 wt.%
 Oil / Gas formed by matured rock migrates.
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13. Reservoir Rock
 An element of petroleum system that can accumulate hydrocarbon. Rocks are able to
store the fluids (water, oil and gas) inside its pores.
 Reservoir rock must has good porosity and permeability to accumulate oil in
economical quantities.
 Petroleum is ultimately collected through secondary migration in reservoir rock.
 Reservoir rock types most frequently in oil field are sand stone and carbonates
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14. Migration
Primary Migration Secondary Migration Tertiary Migration
Migration of
generated oil / gas
within the source
rock
Migration of generated
oil / gas beyond the
source rock
Leakage of
petroleum to the
earth’s surface due
to absence of trap.
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• The process which petroleum moves from source rock to it’s final destination,
through carrier beds.
• Migration medium- Porous, high permeability
• 3 stages in migration process;

15. Cap Rock/ Seal Rock/ Trap rock15
 Oil and gas are less denser than water. Hence rise upward under buoyancy.
 Further migration of oil / gas is prevented by seal rock.
 Cap rock is an impermeable rock
 Eg:- Shale, Mud stone, Silt stone
 Perfect cap rocks can not be found(100% impermeable)
 Minor cracks might present

16. Types of traps16

17. Timing of petroleum migration
 Timing of petroleum migration is important.
 Relative to the deposition of
 reservoir rock
 seal rock
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1 Source Rock
2 P/T Not a petroleum system
3 Sand Stone
1 Source Rock
2 Sand Stone
3 Mud Stone Petroleum system
4 P/T

18. 18

19. Group Members
 Athputhan S.
 Balasooriya I.A.
 Bandara T.G.T.A.
 Bogahawatte P.M.B.M.V.
 Chiranjaya Y.A.S.U.
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UWU/MRT/15/001
UWU/MRT/15/002
UWU/MRT/15/003
UWU/MRT/15/004
UWU/MRT/15/006